The right is contending that the Constitution is being misinterpreted. If so, the allegation applies to all that are currently here.
You're not talking about passing a new law; you are talking about interpreting the law as is. IF the 14th Amendment was not interpreted to your liking, if it is reinterpreted, it applies to all those benefiting off citizenship while not being citizens.
There seems to be a disconnect with those wanting to crack down on immigration. Let me clear up a myth for you. While there are people waiting to get into the United States, there is no first come, first served line. Some offices process applications faster than others; some individual agents process applications faster than others. In order for what you say to happen, the legislature would have to create a first come first served law.
That clearly is not what this is about. This thread is about Trump ending birthright citizenship without amending the Constitution. He can't do it and you've uncovered one reason why it would be impractical for him to do so. He'd still need the legislature to pass laws to make it work. It would be more straightforward and simple to merely have the 14th Amendment declared null and void since it was not legally ratified as per the law. There would be some problems - an adjustment period, but that would be the fastest and simplest solution.